[PATCH v2 0/4] BCM283x Camera Receiver driver

[Hans Verkuil]

On 13/09/17 17:49, Dave Stevenson wrote:
> OV5647
> 
> v4l2-compliance SHA   : f6ecbc90656815d91dc6ba90aac0ad8193a14b38
> 
> Driver Info:
>     Driver name   : unicam
>     Card type     : unicam
>     Bus info      : platform:unicam 3f801000.csi1
>     Driver version: 4.13.0
>     Capabilities  : 0x85200001
>         Video Capture
>         Read/Write
>         Streaming
>         Extended Pix Format
>         Device Capabilities
>     Device Caps   : 0x05200001
>         Video Capture
>         Read/Write
>         Streaming
>         Extended Pix Format
> 
> Compliance test for device /dev/video0 (not using libv4l2):
> 
> Required ioctls:
>     test VIDIOC_QUERYCAP: OK
> 
> Allow for multiple opens:
>     test second video open: OK
>     test VIDIOC_QUERYCAP: OK
>     test VIDIOC_G/S_PRIORITY: OK
>     test for unlimited opens: OK
> 
> Debug ioctls:
>     test VIDIOC_DBG_G/S_REGISTER: OK (Not Supported)
>     test VIDIOC_LOG_STATUS: OK
> 
> Input ioctls:
>     test VIDIOC_G/S_TUNER/ENUM_FREQ_BANDS: OK (Not Supported)
>     test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
>     test VIDIOC_S_HW_FREQ_SEEK: OK (Not Supported)
>     test VIDIOC_ENUMAUDIO: OK (Not Supported)
>     test VIDIOC_G/S/ENUMINPUT: OK
>     test VIDIOC_G/S_AUDIO: OK (Not Supported)
>     Inputs: 1 Audio Inputs: 0 Tuners: 0
> 
> Output ioctls:
>     test VIDIOC_G/S_MODULATOR: OK (Not Supported)
>     test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
>     test VIDIOC_ENUMAUDOUT: OK (Not Supported)
>     test VIDIOC_G/S/ENUMOUTPUT: OK (Not Supported)
>     test VIDIOC_G/S_AUDOUT: OK (Not Supported)
>     Outputs: 0 Audio Outputs: 0 Modulators: 0
> 
> Input/Output configuration ioctls:
>     test VIDIOC_ENUM/G/S/QUERY_STD: OK (Not Supported)
>     test VIDIOC_ENUM/G/S/QUERY_DV_TIMINGS: OK (Not Supported)
>     test VIDIOC_DV_TIMINGS_CAP: OK (Not Supported)
>     test VIDIOC_G/S_EDID: OK (Not Supported)
> 
> Test input 0:
> 
>     Control ioctls:
>         test VIDIOC_QUERY_EXT_CTRL/QUERYMENU: OK
>         test VIDIOC_QUERYCTRL: OK
>         test VIDIOC_G/S_CTRL: OK
>         fail: v4l2-test-controls.cpp(587): g_ext_ctrls does not
> support count == 0

Huh. The issue here is that there are no controls at all, but the
control API is present. The class_check() function in v4l2-ctrls.c expects
that there are controls and if not it returns -EINVAL, causing this test
to fail.

Try to apply this patch:

Signed-off-by: Hans Verkuil <hans.verkuil at cisco.com>
---
diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index dd1db678718c..4e53a8654690 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -2818,7 +2818,7 @@ static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
 static int class_check(struct v4l2_ctrl_handler *hdl, u32 which)
 {
 	if (which == 0 || which == V4L2_CTRL_WHICH_DEF_VAL)
-		return list_empty(&hdl->ctrl_refs) ? -EINVAL : 0;
+		return 0;
 	return find_ref_lock(hdl, which | 1) ? 0 : -EINVAL;
 }


and see if it will pass the compliance test. There may be other issues.
I think that the compliance test should handle the case where there are no
controls, so this is a good test.

That said, another solution is that the driver detects that there are no
controls in unicam_probe_complete() and sets unicam->v4l2_dev.ctrl_handler
to NULL.

I think you should do this in v4. Having control ioctls but no actual controls
is not wrong as such, but it is a bit misleading towards the application.

But let's make sure that v4l2-compliance can handle this case first.

Regards,

	Hans